Amalgam mulling container

ABSTRACT

Disclosed is a mulling cup for use with amalgam machines. The cup includes a polyurethane insert for directly receiving the amalgam ingredients, the resiliency of the insert reducing the time necessary to produce an amalgam while greatly increasing the life expectancy of the mulling cup.

Unite States atnt [191 Lentine et a1.

[ Mar. 18, 1975 AMALGAM MULlLllNG CONTAINER Inventors: Frank N. Lentine, Taylor; Harold H.

Simpson, Fraser, both of Mich.

Assignee: Sybron Corporation, Rochester,

Filed: Jan. 18, 1974 Appl. N0.: 434,509

U.S. Cl 241/102, 241/284, 241/D1G. 30

Int. Cl. B02C 17/22 Field of Search 241/102, 175, 182, 199.5, 241/284, DIG. 30

References Cited UNITED STATES PATENTS 5/1961 Podmore et a1. 241/175 X 10/1963 Suensson 241/102 Primary Examiner-Granville Y. Custer, Jr.

Assistant Examiner--Howard N. Goldberg Attorney, Agent, or FirmTheodore B. Roessel; Roger Aceto [57] ABSTRACT Disclosed is a mulling cup for use with amalgam machines. The cup includes a polyurethane insert for directly receiving the amalgam ingredients, the resiliency of the insert reducing the time necessary to produce an amalgam while greatly increasing the life expectancy of the mulling cup.

7 Claims, 5 Drawing Figures AMALGAM MULLING CONTAINER BACKGROUND OF THE INVENTION The present invention relates generally to dental amalgam machines of the type disclosed, for example, in US. Pat. No. 3,170,648. More specifically, the present invention relates to an improved mulling cup for use with such machines.

In a typical amalgam producing machine, the amalgam ingredients are placed in a metallic cup and the cup spun on its axis in one direction while being rotated in an orbit about a vertical axis in an opposite direction. Centrifugal force acting on the amalgam ingredients fling the ingredients against the wall of the cup. In this way, the ingredients are kneaded together to produce the amalgam.

The amalgam ingredients are fairly abrasive, so that after a period of time, the interior of the mulling cup becomes pitted which causes the amalgam to stick to the walls of the cup. For this reason the metallic cups as used in the prior art must be periodically replaced, usually after about 250 cycles of operation wherein each cycle in approximately to 12 seconds long. The mulling cup of the present invention, however, not only greatly increases the life expectancy of the cup to about 2,000 cycles of operation, but also reduces the cycle time required to produce a satisfactory amalgam by several seconds.

SUMMARY OF THE INVENTION The present invention may be characterized in one aspect thereof by the provision of a cupshaped metallic body portion adapted to connect to the rotor of an amalgam machine, the internal profile of the body portion being generally U-shaped in vertical cross section; a removable cup-shaped insert fitted to the body portion for directly receiving the amalgam ingredients, the insert being made of a resilient material such as polyurethane, so that during the rotation, the amalgam ingredients will deform the insert thereby increasing the area of surface contact between the amalgam ingredients and the insert; and a cover threadably connected to the body portion for securing the insert therein.

OBJECTS OF THE INVENTION One object of the present invention is to provide a mulling cup for use with amalgam machines which reduces the time needed to prepare the amalgam over mulling cups of the prior art.

Another object of the present invention is to produce a mulling cup for use with amalgam machines having a greater life expectancy than cups of the prior art.

A further object of the present invention is to provide a mulling cup for use with amalgam machines wherein the cup has a metallic body portion and a polyurethane insert.

A still further object of the present invention is to provide a mulling cup for amalgam machines having a disposable insert.

These and other objects advantages and characterizing features of the present invention will become more apparent upon consideration of the following detailed description when taken in connection with accompanying drawings depicting the same.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partly broken away and in section showing a portion of the amalgam producing machine mounting the mulling cup of the present invention;

FIG. 2 is a cross section of the mulling cup insert on an enlarged scale taken along lines 22 of FIG. 1;

FIG. 3 is a plan view of the :insert on an enlarged scale;

FIG. 4 is a view showing the amalgam ingredients against the wall of a prior art metallic mulling cup; and FIG. 5 is a view similar to FIG. 4 only showing the mulling cup of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 shows the mulling cup of the present invention generally indicated at 10, the cup being attached to the rotor of an amalgam producing machine, a portion of the rotor being shown at 12. It should be appreciated operation of amalgam pro ducing machines are well known. in the art and that it is sufficient for purposes of the present invention merely to say that rotor I2 is driven about a vertical axis indicated at 14. At the same time, mulling cup 10 is rotated in an opposite direction about its axis indicated at 16. Consequently, the mulling cup rotates about its vertical axis while orbiting around rotor axis 14.

As mulling cup I0 spins on its own axis in a direction opposite to the direction of rotor rotation, certrifugal force acts to knead the mass of amalgam ingredients within the cup so as to work or mull the ingredients against the interior walls of the cup to form the amalgam. In order to spin mulling cup 10 about its own axis, rotor 12 carries a hollow shaft I8, which is mounted for rotation in bearing 20. A spur gear 22 fixed to the bottom of the shaft is driven through a gear train (not shown) as rotor 12 rotates about axis 14. The rotation of shaft 18 is imparted to the mulling cup by means of pins 24, which are releasably captured in slots 26 formed in bottom of the mulling cup.

Mulling cup 10 is shown to include a body portion 28, a removable insert 30 and a cover member 32. Body portion 28 is a metallic cup having an open end 34 and a closed end or base 36. The base is provided with slots 26 for receiving pins 24 (FIG. 1) and is also provided with a dowel 38 which is received into a corresponding bore 40 in hollow shaft 18.

The internal surface of member 28 is generally U- shaped in cross section with the internal base surface 42 smoothly merging with the internal wall surface 44. This configuration permits a close intimate contact between the internal surface of the body portion 28 and exterior surface of insert 30.

Insert 30 has an exterior profile generally U-shaped and cross section to closely match the internal profile of body member 28 so that the insert will snuggly nest in the body member. The insert is made of resilient material preferably polyurethane for purposes set out herein below. The internal surface of insert 30 has its lower portion provided with a plurality of flutes 46 as best seen in FIG. 2. These flutes assist in the mulling or working of the amalgam ingredients as the ingredients are rolled from one flute of the cup to the next during rotation. The upper portion of insert 30 is necked, so that the internal diameter of insert opening 48 is less than the diameter taken across the fluted portion (compare, for example, the cross section as shown in FIG. 2 and the plan view shown in 3). This arrangement tends to prevent centrifugal force from throwing the amalgam ingredients out of the cup.

Cover 32, which is threaded to body member 28, extends across the upper end 50 of the insert for purposes of firmly retaining the insert in the body portion.

Actual test results have shown that the mulling cup constructed in accordance with the present invention, including the resilient insert, is capable of producing an exceptable dental amalgam several seconds faster than the prior art metal mulling cup.

Actual tests also established that the metallic cup was eroded and pitted by the amalgam ingredients to such an extent after only 250 cycles of operation, that replacement of the cup was necessary. In contrast, the mulling cup of the present invention, operated for over 2,000 cycles before it became necessary to replace the insert.

Not only does the mulling cup of the present invention have a longer life expectancy than the metal cup of the prior art, but also when replacement is necessary, only the less expensive insert need be replaced as opposed to replacing the entire metallic mulling cup.

It is not understood exactly why the mulling cup according to the present invention is able to produce an acceptable dental amalgam several seconds faster than the metal cups of the prior art. However, one possible explanation is illustrated in connection with FIGS. 4 and 5. FIG. 4 illustrates a mass of amalgam ingredients 52A engaged against the surface 54A of a prior art metallic mulling cup. ln contrast, FlG. 5 shows a mass of amalgam ingredients 52B engaged against the resilient surface 548 of a mulling cup according to the present invention. With the metallic cup, the amalgam ingredients 52A merely lay against the surface 54A of the cup. With a resilient cup, however, the cup material gives," so that the amalgam ingredients may embed in the resilient surface 548. Consequently, there is a greater surface contact between the amalgam ingredients and the resilient surface than in the case of the unyielding metallic surface 54A. Since thereis a greater surface area of contact, this means that more work can be imparted to the amalgam ingredients as the ingredients are flunge by certrifugal force around the interior of the cup. It is believed that it is this greater area of contact, with the resulting transference of a proportionally greater amount of work to the amalgam ingredients, which causes a faster amalgamation of the ingredients in the present invention than in the metallic cups of the prior art.

Thus, it should be appreciated that the present invention accomplishes its intended objects in providing a mulling cup for amalgamating machines, which not only has a greater life expectancy over metallic mulling cups of the prior art, but which also is capable of producing a satisfactory amalgam several seconds faster than metallic cups of the prior art. The mulling cup of the present invention and particularly the polyurethane insert has proved to be much more resilient to the abrasiveness of the amalgam ingredients, so that its life expectancy is approximately 10 times the life expectancy ofa metal cup. Further, even when replacement is necessary it can be accomplished cheaply since the insert, which can be injection molded, for example, is rela tively inexpensive as compared to a metallic cup having the same internal configuration.

We claim:

1. In an amalgam producing machine including a rotor member, a cup for reception of the amalgam ingredients comprising:

a. a body portion having an open end and a closed end including means for connecting said body portion to said rotor for rotation in an orbital path about a vertical axis laterally spaced from the axis of rotation of said rotor;

b. a removable cup-shaped insert fitted to said body portion for directly receiving the amalgam ingredients, said insert being of a resilient material so that upon rotation in said orbital path centrifugal force will cause said amalgam ingredients to strike and deform the wall of said insert promoting mulling of said ingredients; and

c. means positionable over said insert and connectable to said body portion for securing said insert in said body portion.

2. A cup as in claim 1, wherein the external configuration of said insert is generally U-shaped in cross section with the base of said insert being arcuate.

3. A cup as in claim 2, wherein the internal surface of said body portion is configured to nest with the exterior configuration of said insert.

4. A cup as in claim 2, wherein the internal surface of said insert adjacent the base thereof is fluted.

5. A cup as in claim 1, wherein the internal diameter adjacent the base of said cup-shaped insert is larger than adjacent the open end of said insert.

6. A cup is in claim 1, wherein said resilient material is polyurethane.

7. A cup as in claim 1, wherein said means is a cap threaded to said body portion, said cap having a central 

1. In an amalgam producing machine including a rotor member, a cup for reception of the amalgam ingredients comprising: a. a body portion having an open end and a closed end including means for connecting said body portion to said rotor for rotation in an orbital path about a vertical axis laterally spaced from the axis of rotation of said rotor; b. a removable cup-shaped insert fitted to said body portion for directly receiving the amalgam ingredients, said insert being of a resilient material so that upon rotation in said orbital path centrifugal force will cause said amalgam ingredients to strike and deform the wall of said insert promoting mulling of said ingredients; and c. means positionable over said insert and connectable to said body portion for securing said insert in said body portion.
 2. A cup as in claim 1, wherein the external configuration of said insert is generally U-shaped in cross section with the base of said insert being arcuate.
 3. A cup as in claim 2, wherein the internal surface of said body portion is configured to nest with the exterior configuratioN of said insert.
 4. A cup as in claim 2, wherein the internal surface of said insert adjacent the base thereof is fluted.
 5. A cup as in claim 1, wherein the internal diameter adjacent the base of said cup-shaped insert is larger than adjacent the open end of said insert.
 6. A cup is in claim 1, wherein said resilient material is polyurethane.
 7. A cup as in claim 1, wherein said means is a cap threaded to said body portion, said cap having a central opening. 